Steam power plant



Jan. 22, 1946. A. DQBLE STE'AM POWER PLANT Filed om.kv l21, 1944lPatented Jan. 22, 1946 A STEAM POWER PLANT Abner- Doble, Chicago, Ill.,assigno'r to Stanley Steam Motors Corporation, Chicago, Ill., acorporation of Delaware Application October 2l, 1944, Serial No. 559,750

(Cl. (so- 106) v 18 Claims.

This invention relates to power plants employing steaml or other elasticfluids or vapors, and more particularly to steam power plants of smallsize but large capacity l or installation in vehicles, for example, anautomotive vehicle, and the invention has for an object the provision ina power plant of this character of means for performing the auxiliaryfunction of utilizing fluid from the boiler at an intermediate stage ofvapor generation for use in jackets of the engine as a cooling orheating medium depending upon the operating conditions of the engine;and as a further object to provide a plant capable of being usedalternatively for propelling the vehicle or as a braking means.

In a power plant having small physical dimensions and large horsepoweroutput it is desirable to use steam at high pressures and in a highrange of superheat in order to derive the maximum useful energy from thefuel used for heating the boiler. For example, by using materials nowavailable for the construction of the parts subjected to these highpressures and temperatures it is possible to operate a power plant ofthe character described with steam at a pressure as high as 2000 poundsper square inch and having a total temperature, including su'perheat, of1200 F. or more. However, when operating with steam at such temperaturesgreat difficulty is encountered with lubrication of the valves andpistons. It is of course necessary that-the lubricant used remain at theproper viscosity and chemical state, regardless of the temperature ofthe steam being circulated in the engine Accordingly, there have beensuggested in the prior art various means of maintaining the walls of thecylinder, cylinder heads and piston at a temperature low enough forproper lubrication to counteract the destructive effect thereon of thehigh temperature of the steam. Such prior structures have included theuse of water or other fluids circulated about the engine parts. or thepassage of Water from the boiler at some stage in its transition Afromwater to steam and recirculating that water or steam back to the boiler,In the latter arrangement no means was provided to coordinate thetemperature of the water to be circulated with the operating demands ofthe engine, or no region specified in the boiler 'wherefrom the watershould be drawn or whereto it should be returned. Accordingly, a furtherobject of the invention is the i. e., for use in vehicles, it is highlydesirable to utilize the pistons and cylinders of the engine in areverse manner to render them active as a compressor mechanism, wherebythe resistance of the steam to a force applied to the piston iseffective as braking means to decelerate the motion of the vehicle. Thedesirability of this feature becomes evident when the momentum of alarge vehicle such as a bus or truck must vbe absorbed to reduce thespeed thereof on a grade, or to bri-ng the vehicle to rest. By drivingthe engine from the wheels through the transmission and clutch a mosteffective braking vmeans is provided, and wear on the brake linings ofthe wheels or' drive shaft is materially reduced. The compression of thesteam results in the production of a large amount of lheat and the waterjacket is utilized to dissipate this heat. Hence a further object isprovision of means for cooling those moving parts of the engine whoselubrication may be impaired by steam at high temperatures.

In power plants of the general type mentioned,

the yprovision of a-n efficient braking system together with meansadapted to convert rapidly the propelling engine to a. brakingmechanism.

In carrying out the invention in one form, a power plant is providedcomprising an engine and a boiler including two sets of coils. Fluidenters one set of coils and flows therethrough until it attains atemperature suitable for use in cooling the lubricated areasl wherefromit is circulated through the jackets provided in the engine thereforand,v after performing its function returned to the other set of coilsand heating thereof continued to lproduce vapor for feeding the engine.n

In connection with a power plant embodying a. multiple-expansion engine,e. g., having a highpressure stage, an intermediate-pressure stage., anda low-pressure stage, another object resides in using the uid from theboiler not only to create .the best condition for lubrication, but tomaintain the walls of the low-pressurev cylinder at a temperatureconsiderably higher than the saturation-temperature corresponding to thepressure of the steam employed in that cylinder, thereby preventingundue loss of efficiencyby condensation of the steam in the cylinder,and resulting in a feature of decided advantage when operating at lightloads. l f

In a power plant operating on steam at 1500 pounds per square inch, forexample, the Water in the boiler would boil at approximately 600 F.,

and .the heat content of water at that temperature would be effectivefor the purposes above outlined. In certain types of installations, inorder to attain a proper cooling effect it may be found more desirableto 4draw the water tobe circulated from the economizer-zone of theboiler at a temperature lower than that of evaporation.

A further object gained by circulating water from a selected zone of theboiler is the safeguarding of the material from which the cylinders,valve housings, and other parts in contact with the incoming steam areconstructed, from the injurious effects of high temperature.Furthermore, by maintaining a well-heated engine during idling or beforestarting, the engine is allowed to operate at high eiiiciency and withhigh starting torque,

In carrying out the invention in its other aspect of employing theengine as a braking means, the

valve-gear is so proportioned as to yield inlet and delivery, timing ofthe valves for smooth compression and the elimination of uneven torque.By suitable mechanism to be described hereinafter, the engine may beinstantaneously converted from propelling action to braking action sothat the pistons and cylinders serve as a compressor, drawingsteam fromthe condenser and compressingA the same to generate heat which heat istransferred to the jacket-water and thus to the boiler, which results inthe formation of steam and an increase in boiler-pressure. Ex-

-cess pressure so created is relieved through a suitable valve to thecondenser, and therefrom to the hot well. During the braking periods, nosteam reaches the condenser from the engine, so that the condenser is ofample capacity to accom,-

modate the excess steam engendered by the braktrol in combination withthe thermostat to start and stop ow of feed-water through the pump.Therefore,y when thev engine acts as a brake, means are provided totransfer the control of the feed-pump from the pressure-control andboilerthermostat jointly to the boiler-thermostat solely.

For a more complete understanding of the invention, reference should nowbe had to the drawing in which the invention is illustrateddiagrammatically as embodied in a power plant, comprising a steamgenerator or boiler Iwhich incorporates two sets of coils II and I2. Incoil II the water circulates and is raised from feedwater temperature tothat temperature desired to 23 driven from the main shaft 20 of `theengine and reciprocating a piston 24 through a connecting rod 25. Bymeans of pipe 21 the cylinder 26 is in communication with the valvechamber 28. The latter connects with a pipe 29 extending from the waterin the hot-well 3|. The valve chamber 28 includes the inlet port 32 andthe outlet port 33 adapted to be closed by valves 34 and 35respectively. Adapted to actuate the valve 34 is the push rod 4I formingan extension of the armature 40 of a solenoid d2. A spring 44 constantlyurges the armature 40 and its push rod 4I upwardly. The chamber 28 is incommunication with the boiler coil AII through conduit 43.

Arranged within a suitable pocket 5| of the coil I2 and in a zonecorresponding to the boiling point of the lwater in the boiler under allconditions of boiler-load, is the thermostat 52 comprising an elongatedsleeve 53 of relatively small diameter compared to its length, andconsisting of metal which changes rapidly in dimensions under varyingtemperatures, closed at the inner end and having attached thereto acontrol rod 54. |I'he outer extremity of the rod 54 is adapted tooperate a pivoted lever 55 and a spring 56 lbiases the lever intooperative contact with the rod 54.

Thev lever y operates two sets of electrical contacts shown at 6I and62, -those at 6I being open when rod 54 is to the left corresponding toa low-temperature condition of the thermostat 52 and those at 62 beingat that time closed. Contacts I6I are closed by a movable member 51having a slotted aperture 58 engaging a pin 59 and having interposedbetween it and the lever 55 the spring 60, so that member 51 which isdisengaged from the contacts 6I when the lever 55 is to the left, willmove to close the contacts 6I when the lever '55 moves to the rightyandv after the contacts 6I are closed the spring 6l) yields to permitadditional movement of the lever effect the objects aforementioned, andin coil I2 illustration there is shown a carburetor I3 feeding fuel to aVenturi tube I4 through which air for combustion is forced bya blower I5driven by an electric motor I6. A spark plug I1 ignites the fuel and airmixture. Products of combustion pass from the boiler through an exhaust2|.

For supplying water to the boiler there is provided a feed-pump 22comprising a crank-shaft 55 to the right so as to operate the member 62ato open the contacts 62. Upon leaving the coil I I the boiling waterpasses through a conduit 63 to the jackets 64 of the engine 65.For'clarity, only one cylinder and its jacket are shown, but it will beunderstood that the watervmay be circulated through all jackets of theengine, regardless of the number of cylinders or their construction, andfurthermore, by suitable means, not shown, the water may be circulatedthrough the piston rods and pistons. It will be understood that insteadof double walls as shown, to form the jackets, there may be providedtubing wound or otherwise shaped to follow the contours of the engineparts and cast integrally with the parts themselves, e. g., ahelically-wound tube could be cast around the cylinder. Afterperformingits function of heating or cooling, as the case may be, in the engine,the water is returned through conduit 66 to the coil I2 wherein it istransformed `into steam or superheated if alreadyin the form of steam,and fed through branch 61 to the steam main 6B.

Admission of steam to the engine is by a throttle 1I and branch 12, andexhaust thereof from the engine is through conduit 13 to the condenser14. Condensation is returned to the hot well 3| by a conduit 15.

Connected to the main 58 by a branch 8l is the safety valve 82 by meansof which any excessive pressure in the steam feed system is relieved topass through the conduits 83 and 84 to the condenser 14. Also connectedto the main 68 is the .ductor |36, solenoid 42 to ground |32. Hence.

pressure switch 85 actuable by steam pressure to operate a lever 86carrying one oi' a pair oi' contacts 81, the other being ilxed.

Steam main 68 isvalsoprovided with a brakingcontrol valve 9| including ahandle 92 carrying a link 93 pivoted thereto at one end at 94. The

link 93 is extended at its opposite end into a yoke l including anelongated aperture 95 with whichv engages a stud 96 carried on one endof the handle 91 adapted to operate the forward-reverse" valve 98.Movement of the handle 91 effects operation of the valve-gear of theengine for manipulating the same into position for forward or "reversepropelling action, Since the valve-gear may be of any preferred type andthe invention is applicable to an engine having any type of valve-gear,the same is not illustrated or further described.

Adapted to be actuated by the extremity 99 of the link 93 is the bellcrank lever |03 pivoted at |04 and normally biased clockwise as shown bya Y spring |05. At each end of the transverse arms of the lever |03 arethe movable members of the pairs of contacts |06 and |01 for a purposeto be described. i

Interposed inthe main 68 -is the pedal-controlled relief valve providedwith a member ||2 seating against the spring ||3. Valve may be ofseveral different constructions, as for example, including a valve seatand disc pressed thereagainst by the spring ||3, the pressure of saidspring being relatively light for a purpose to be explained, but adaptedto be compressed further by pressure applied to the pedal I4. Althoughfor convenience I describe the Valve as pedalcontrolled it will beunderstood that I comprehend thereby any valve under the control of theoperator of the vehicle, and therefore. that when used in thedescription and claims, the phrase pedal-controlled is to be given thatmeaning.

Discharge through the valve is through the and at the other to a mastercut-ofi switch |33.

A conductor |34 connects to the ilxed member of contacts 81,. and aconductor |35 connects the lever 86 carrying the other of the contacts81`to one of each of the contacts 6| and 62. The remaining one ofcontacts 6| is connected by a conductor |36 to one terminal of thesolenoid 42, the other terminal being connected to ground |32. Theremaining one of contacts i62 is connected by a conductor |31 to thelever |03. A conductor I4|, together with conductor |34, serves toconnect the fixed member of contacts |01 to the battery |3|.

The motor I6 is connected by one terminal to ground |32 and bythe otherthrough conductor |42 to the fixed member oi contacts |06.

Assuming that the boiler I0 is operating during either propellingA orbraking and is demanding water, the feed pump 22 will be supplying waterto the coil During this period the solenoid 42 is energized, since thethermostat 52 is expanded, rod 54 is to the right, and contacts 6| areclosed to form a circuit including ground |32, battery |3|, closedswitch |33, conductor |34, closed contacts 81, conductor |35, closedcontacts 6|, conrod 4| assumes its lower position against the spring 44to permit the valve 34 to occupyiits lport 32. Now the pump will operatenormally,

suction occurring through the valve 34, and discharge through the valve35 and conduit 43 to the coil I i Simultaneously a circuit exists forblower motor il, the-same being traced from ground |32, conductor |42,closed contacts |06, lever |03, conductor |31, closed contacts 62,conductor |35, closed contacts 61, conductor |34, switch |33, and

battery |3| to ground |32, so that the fuel mixand I2 is 'selected sothat water will preferably be extracted from thel boiler at atemperature corresponding to the boiling point at the pressure existingin the boiler under all conditions of boiler-load. i. e., near thebeginning of the evaporation zone. l

After its circulation through the jackets 64 the water, or under someconditions water and/or steam, is returned to the coil |2'where itsconversion into steam and superheating to the desired f degree iscompleted, and the same fed to the main 68 by way of conduit 61. Steamis admitted to the engine by means of throttle 1| and branch 12, exhaustoccurring through conduit 13 to the condenser 14.

For regulation of the pressure of the steam being delivered to theengine. and hence1 of the temperature of the boiling water beingcirculated through the jackets 64, the thermostat 52Y is employed. Asthe temperature of the steam and/or Water existing in the pocket 5|rises, the sleeve 53 expands in length vto move the rod 54 to the rightand permit the lever 55 to swing clockwise under urging of the spring56.

When the supply of feed water to the boiler is suiiicient to cause theboiler temperature to decrease, the thermostat 52 will contract so thatlever 55 moves counterclockwise and opens contacts 6|.l Thus the circuitto solenoid 42 isinterrupted and the spring 44 operates to raise the rod4| and thereby lift valve 34 from its seat. Accordingly pump 22 isineffective to feed water to the boiler since the pump will merely drawwater through the port 32 and discharge through the same to the weil 3I, and none will pass through the valve 35 which is maintained closed bypressure in the boiler.

As the steam pressure f temperature) falls upon consumptionnthereof, thethermostat 52 contracts to permit contacts '62 to re-ciose and returnthe motor |6 and blower I5 to active duty. The resulting increased rateof evaporation Within the boiler causes a rise in boiler temperature anddictates a restoration of feed of water to the boiler. Accordinglythermostat 53 expands to permit contacts 6| to be closed by member 51 toenergize the solenoid 42 and thereby reestablish flow of boiler feedwater through the valve.

35 to make up for the increased rate of evaporation within the boiler.Further movement of the rod 54 to the right will move member 62a to opencontacts 62 to de-energize the circuit heretofore traced for the motor|6, and the fuel mixture is cut oil.

It will be noted that the pressure switch 85 comprising the contacts 91will operate under excessive pressure in the main 68, so if that eventoccurs contacts 81 will open to break the circuit for both the motor I6and the solenoid 42,

and permit the pressure to drop, whereupon the circuit isre-established.

By interposing the thermostat 52 in the coil I2 at a positioncorresponding to the return of the water from the jackets 64, it ispossible to secure control of the jacket temperature in proportion tothe quantity `of heat required by the jackets. For example, if atstarting or upon operation at light loads` the jackets require more heatdue to the cooling effected by the low pressure steam used at lightloads or the drop in pressure incident upon starting, the circulatingwater is thus cooled to a greater extent, and the thermostat acts toraise the boiler temperature to the level necessary to supply thatadditional heat. Thus the engine is enabled to oper-- ate powerfully andeconomically as soon as it is started and reduces to a negligible degreeany risk of damage due to water in the cylinder. In

large cylinders the likelihood of cracking of the cylinder-casting byuneven expansion of the metal is materially reduced. g

Inasmuch as the thermostat acts to maintain constant the temperature ofthe steam delivered by the boiler, another valuable result is secured;viz., assuming that the engine has been operating under a light loadwith short cut-off. Under that condition the cylinder-walls will requiremore heat than when operating under a heavy load and this heat must betaken from the water in the jackets in order to produce a balancebeproach a higher boiling point.

the cylinder-walls require more heat to balance tween the temperaturesof the water and steam.

Such heat must be supplied by the boiling Water and accordingly moreheat must be applied to the boiler to raise the temperature of the watertherein. Decrease of the temperature of the water in the boiler resultsin a lowered rate of generation of steam. To re-establish the requiredrate of steam flow to the cylinder to compensate for the increasedcondensation at light load, the drop in pressure (temperature) in coilI2'and thermostat 52 will reclose the contacts 62 and start the blower I5 to increase the temperature of the steam being supplied by the boiler.When proper equilibrium has been reached between the steam in thecylinder and the water in the jackets the thermostat will reverse itsaction. Thus constant regulation as just outlined will occur.

Now, assume the throttle 1I suddenly to be opened wide. Less heat isrequired by the jackets, `or stated otherwise, a new condition ofbalance must be reached between the water and steam, the jacket watertending to be raised to the temperature of the steam in the cylinder,and that steam tending to approach in temperature that of the water.Increased ow of steam from the boiler resultsv in correspondinglyincreased flow of water through the jackets, for, in reality, coils iIanad I2 are in series, the jackets being intermediate the, series.jackets accept less heat since their temperature has been increasedsuddenly relative to the temperature of the water in the jackets.However, the increased flow of steam from the boiler has decreased thepressure therein, which lowers the temperature at which water will boilin the boiler. These effects permit the water to leave the jackets at ahigher temperature to operate the thermostat and increase the flow offeed water to ac- At this stage the commodate the increased demand onthe engine.

Afterfull load has prevailed for some period of time, suppose thethrottle 1I be partially closed to, say, one-quarter full load. Pressuredrop through the boiler is not as great, and the pressure thereinincreases to cause the water to ap- Simultaneously the lowered steampressure, and therefore the jackets yield more heat. Hence the waterreaching the thermostat is cooler and it reacts to re- .duce thequantity of feed water and boiler heating,

ForV reversing the engine there is provided the handle 91 controllingthe valve 98 to admit live steam through the branch IIII to operate thevalve gear of the engine, steam being exhausted through the conduit I02to the condenser. Although any suitable mechanism manually orpower-operated, for actuating the valve gear .from forward to reverse orvice versa in accordance with the movements of the lever 91, may beemployed, a preferred form of reversing mechanism is described andclaimed in my copending application Ser. No. 518,517, filed onJanuary-17, 1944. drawing the handle 91 is in forward and upon beingswung clockwise it would be in reverse." For convenience the handle 91will be hereinafter referred to as the forward-reverse control.

The valve 9| will be referred to as the braking-control and its functionwill now be described. In the position shown for the brakingcontrol 9Ithe engine is in normal propelling operation and braking is effected by'use ofthe pedal II4 operating through-the valve II1, the

usual air or hydraulic brakes being employed.

desired to use the engine in its braking function,

the handle 92 is moved to the right to actuate the link 93. This in turnrotates the forwardreverse handle 91 clockwise through stud 96 whereuponthe braking control valve 9i is opened to permit exhaust steam from theengine to pass through the valve I I I. Simultaneously the valve 98 isoperated to permit live steam to actuate the valve-gear to reverse,exhaust from the operating cylinder passing through the conduit |02 tothe condenser 14. Admission of steam to the valve III and shifting ofthe valve-gear to reverse, conditions the brake pedal II4 and the valvegear for engine-braking. The pressure of the spring II2 is such thatnotwithstanding there may be no actuation of the pedal II4 by theoperator, throttling of the exhaust steam through the valve I II exertsa back-pressure on the piston and results in braking of the vehicle bythe engine. However, if additional braking force is required theoperator presses the pedal I I4 to increase the force of the spring I I3to produce a greater back-pressure. The extremity 99 of the link 93,upon movement thereof, strikes the downwardly extending arm of the lever|03 to open contacts |06 and to close contacts |01.

Inasmuch as during braking action the engine remains connected inpropelling relation with the wheels of the vehicle, the. momentum of thevehicle is, during such action, imparted through the wheels to theengine, so that the engine is over-driven.

Since during braking there is no need for generation of'steam, theopening of contacts |06 In the position shown in the cuts off the blowermotor I6', the circuit therefor v having previously been traced asincluding the contacts |06. Due to reversal of the valve gear and thebraking action of the engine to be described more fully hereinafter, thesteam pressure will rise in the main 68 to. operate the control 85 androck the lever 86 counterclockwise to open the contacts 81. Thusthecircuit from the battery I3| to the solenoid 42 will be interruptedregardless of whetherv the contacts 6I are open or closed under controlof `the thermostat 52. Accordingly it is necessary to set up analternative circuit for the feed pump 22, which may be traced frombattery |3i, through conductor |34, conductor |4I, closed contacts |01,conductor |31, contacts 62, contacts 6I, conductor |36, solenoid 42 toground |32. However, thermostat 52 still retains its control asheretofore set out. l

With the valve gear in reverse the heat generated by the compression ofthe steam within the cylinder is transferred to the jackets, therebyincreasing the heat content thereof, so that when that water returns tothe boiler there results increased formation o f steam and an increasein boiler-pressure. Relief thereof occurs through branches 61, 8|, safey valve 82, exhaust lines 83 to 84 to the condenser 14. It will beunderstood that, during braking periods, no steam reaches the condenserfrom the engine, so that the condenser capacity is not overtaxed byrelief through the valve 82.

However, it is essential that the feed pump be maintained in operationduring engine-braking, since the heat supplied to the boiler l willgenerate additional steam therein, and feed-water must be supplied,otherwise the steam being generated may reduce the quantity of water inthe boiler to a dangerous level. The circuit for thel feed pump has justbeen traced.

Referring again to the braking control 9|, it

will be noted that when engine-braking is not desired the link 93 is tothe left, but in virtue of the slot 95, the forward-reverse lever 91 maynevertheless be operated to either of its positions without disturbingthe link 93.

While I have shown a particular embodiment of my invention,it will beunderstood, of course, that I do not wish to be limitedv thereto sincemany modifications may bev made, and I, therefore, contemplate by theappended claims to cover any such modications as fall within the .truespirit and scope of my invention.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1.. In a power plant including a generator for supplying vapor to avapor engine, the combination comprising a rst set of passages in thegenerator, a second set of passages in the generator, means forsupplying fluid to said first set of passages, chambers in the engineadjacent those lubricated parts thereof subjected to the heating effectof the vapor supplied to the engine, a conduit between the outlet fromsaid first set of passages and said chambers, a conduit between the saidchambers and the inlet to said second set of passages,temperature-responsive means adjacent the inlet to said second set ofpassages and in heat-exchanging relation with the medium therein, aconduit between the outlet from said second 'set of passages and thevapor chest of the engine, and means under the control of saidtemperature-responsive means for controlling said first-mentioned means.

2. In combination, a steam engine including a cylinder, means forming ajacket for said cylinder, steam-generating means including a boiler forsupplying superheated steam to said cylinder, in-

let and outlet means connecting said/jacket to the boiling zone in saidboiler wherebyboiling water flows from'said boiling zone through saidjacket "in heat-exchanging relation with the walls of said cylinder andreturns to Said boiling zone, and thermostatic means responsive to thetemperature of the boiling water returning from said jacket forcontrolling said boiler.

3. In a power plant including a generator for supplying superheatedvapor yto a' vapor engine, the combination comprising a rst set of coilsin the boiling point, a set of superheating coils in the generator,means for supplying fluid to said first set of coils, means forming ajacket for parts of the engine subject to contact by the active vaportherein, a conduit between the boiling zone of said first set of coilsand the jacket and a conduit between the jacket and said superheatingcoils whereby boiling fluid may be circulated through said jacket andreturned to the superheating coils, a conduit between the outlet of saidsuperheating coils and the vapor chest of the engine,temperature-responsive means adjacent the inlet to said superheatingcoils and in heat-exchanging relation with the vapor therein, and

means under the control of said temperature-responsive means forcontrolling said first-mentioned means.

4. In a power plant including a boiler for supplying superheated steamto a steam engine, the combination comprising a ilrst set of coils inthe boiler in which water may be brought to the boiling point, a set ofsuperheating coils in the boiler, means for supplying water to saidiirst set of coils, means forming a jacket for parts of the enginesubject to contact by the active steam therein, aconduit between theboiling zone of said iirst set of coils and the jacket and a conduitbetween the jacket and said superheating coils whereby boiling water maybe circulated through said jacket and returned to the superheatingcoils, a conduit between the outlet of said superheating coils and thesteam chest of the engine, temperature-responsive means adjacent theinlet to said superheating coils and in heat-exchanging relation withthe steam therein, and means under the control of saidtemperature-responsive means for controlling said first-mentionedmeans.

5. In a power plant including a boiler for supplying superheated steamto a steam engine, the,

combination comprising a iirst set of coils in the boiler in which watermay be brought to the boiling point, a set of superheating coils in theboiler, means including a pump for injecting water into said rst set ofcoils, means forminga jacket for parts of the engine subject to contactby the active steam therein, conduits adapted to connect said two setsof coils and said jacket for series flow therethrough, the jacket beingintermediate said sets of coils, a conduit connecting the outlet of thesuperheating coils to the steam chest of the engine,temperature-responsive means adjacent the inlet to said superheatingcoils and in heat-exchanging relation with the steam therein, and meansunder the control of said temperature-responsive means and operativelyconnected with said first-mentioned means to initiate and terminateoperation of said pump.

6. In a power plant including a boiler for supplying superheated steamto a steam engine, the

combination comprising a first set of coils in the the generator inwhich fluid may be brought to y boiler in which water may be brought tothe boiling point, a set of superheating coils in the boiler, meansincluding a continuously-operating pump for injecting water into saidrst set of coils, a valve mechanism for said pump, electricallycontrolled means associated with said valve mecha.- nism to initiate orterminate flow of water from said pump, means forming a jacket for partsof the engine subject to contact by the active steam therein, conduitsadapted to connect said two sets of coils and 'said jacket for seriesfiow therethrough, the jacket being intermediate saidsets of coils, aconduit connecting the outlet of the superheating coils to the steamchest of the engine, temperature-responsive means adjacent the inlet tosaid superheating coils and in heat-exchanging relation with the steamtherein, and means under the control of said temperture-responsive meansand connected with said electrically-controlled means.

7. In a power plant including a boiler for supplying superheated steamto a steam engine the combination comprising a water-heating section anda superheating section in said boiler, means forming a. jacket for thoselubricated parts of the engine subject to contact by the active steam,said sections and jacket adapted to be connected in series with thejacket intermediate said sections, a continuously-operating pump forinjecting water into said heating section, a valve mechanism for saidpump, electrically-controlled means lnclu jing a solenoid for actuatingsaid valve mechanism to initiate and terminate ow of water from saidpump, a connection from the outlet of the superheating section to thesteam chest of the engine, temperature-responsive means adjacent theinlet to said superheating section and including a switch, a source ofelectric current, an electrical circuit including said source, switchand solenoid whereby delivery of water from said pump is under thecontrol of the temperature of the steam in said superheating section.

8. In a power plant including a boiler for supplying superheated steamto`a steam engine the combination comprising a water-heating section anda superheating section in said boiler, means forming a jacket for partsof the engine subject to contact by the active steam, said sections andjacket adapted to be connected in series with the jacket intermediatesaid sections, a burner for heating said boiler including a fuel-feedingmeans, a pump for injecting water into said heating section andincluding valve means for initiating and terminating flow of water fromsaid pump, a connection from the outlet of the superheating section tothe steam chest of the engine, temperature-responsive means adjacent theinlet to said superheating section and operatively connected to saidfuel-feeding means and said valve means whereby control of feed-waterfor the boiler and heating thereof is under the control of saidtemperature-responsive means.

9. In a power plant including a'boiler for supplying superheated steamto a steam engine the combination comprising a water-heating section anda superheating section in said boiler, means forming a jacket for thoselubricated parts of the engine subject to contact by the active steam,said sections and jacket adapted to be connected in series with thejacket intermediate said sections, a burner Ior heating said boilerincluding a fuel-feeding means, a pump for injecting Water into saidheating section and including electrically-controlled valve means forinitiating and terminating now of water from said pump, a

connection from the outlet of the superheating section to the steamchest of the engine, said connection being provided with a deviceresponsive to steam pressure, an electrical switch under the control ofsaid device, temperature-responsive means adjacent the inlet to saidsuperheating section and operativelyconnected to a second electricalswitch, a source of electric current,

and an velectrical circuit including said source and said switcheswhereby the control oi the fuelfeeding means and the pump is under thejoint control of said device and said temperature-responsive means.

10. In a power plant for use in traction and for braking including asteam engine having a piston and a cylinder; a steam generator forsupplying steam to the cylinder; means forming a jacket for saidcylinder and adapted for circulation of water in said jacket inheat-exchanging relation with the steam in the cylinder; a throttlevalve for regulating flow of steam tothe cylinder for traction; meansforv reversing the flow of steam to and from the cylinder for Iorward orreverse traction; a braking control valve; and means operativelyinterconnecting said reversing means and said braking control valve;whereby, upon closure of said throttle valve and actuation of saidbraking control valve for braking, ow of steam to the cylinder isreversed and the engine over-driven to yield a braking action.

11. In a power plant for use in traction. and

.for braking including a steam engine having a piston and a cylinder; asteam generator; a heating section and a superheating section in saidgenerator; means forming a jacket for said cylinder; said jacket beingin series fluid communication with said sections and intermediate saidsections, and the water in said jacket being adapted for heat-exchangewith the steam in the cylinder; means for reversing the flow of steam toand from the cylinder for forward or reverse traction; a throttle valvefor regulating ilow of steam to the cylinder for traction; abrakingcontrol valve; and means operatively interconnecting saidreversing means and said brakingcontrol valve; whereby upon closure ofsaid throttle valve and actuation of said braking-control valve theengine is over-driven to yield a braking action and the heat ofcompression of the overdriven engine is transferred to the jacket.

12. In a power plant for use in traction and forv braking including asteam engine having a piston and a cylinder; a steam generator; meansforming a jacket for said cylinder and adapted for circulation of waterin said jacket in heatexchanging relation with the steam in thecylinder; a throttle valve for controlling flow of steam to the cylinderfor forward or reverse traction; a braking-control valve; valve-gearassociated with the engine for controlling flow of steam to the cylinderand adapted to be actuatedvfor forward or reverse traction; meansinterconnecting said braking-control valve and said valve-gear; saidlast mentioned means being adapted to permit actuation of saidvalve-gear by said brakingcontrol valve, and to permit free actuation ofsaid valve-gear when said braking-control valve is in non-brakingposition; whereby upon actuation of said braking-control valve saidvalve-gear is actuated for reverse traction and the engine over-drivento yield a braking action, the heat of compression of the over-drivenengine being transferred to the water in the jacket.

13. A power plant for a vehicle adapted for propelling or braking actionand having a steam engine including a cylinder and piston; comprising ajacket for the cylinder adapted to receive a fluid; said fluid" beingadapted for vheatexchanging relation with the steam in the cylinder; athrottle valve f or regulating flow of steam to the engine for traction;a braking-control valve; valve-gear associated with the engine forcontrolling flow of steam to and from the cylinder and adapted' to beactuated for forward or reverse propelling action of the engineJ meansoperatively interconnecting said valve-gear and said braking-controlvalve to actuate said valvegear for reverse action; whereby upon closureof said throttle valve and actuation of said brakingcontrol valve theengine is over-driven to yield a braking action and the heat ofcompression of the over-driven engine is transferred to the fluid. i 14.A power plant for a vehicle -adapted for propelling or braking actionincluding a steam vengine having a cylinder and a piston; comprising ajacket for the cylinder adapted to receive a' fluid; said fluid beingadapted for heat-exchanging relation with the steam in the cylinder; athrottle valve for regulating iiow of steam to the engine duringpropulsion; a pedal-controlled relief valve; valvegear associated withthe cylinder for controlling the admission of steam thereto and theexhaust of steam therefrom and adapted to be actuated for forward or.reverse propulsion, a braking-control valve, a duct connecting saidcylinder with'said braking-control valve and a second duct connectingsaid brakingcontrol valve with said relief valve, means operativelyconnecting said valve-gear with said braking-control valve,v wherebyupon actuation of said braking-control valve said valve-gear isconditioned for reverse propulsion and the overdriven engine conditionedfor braking action under the control of said relief valve, the heat of ycompressiongenerated in the steam during braking being given up to saidfluid.

cylinder; a throttle valve forregulating ow of v steam to the engineduring propulsion; a pedalcontrolled relief valve; valve-gear associatedwith the cylinder for controlling the admission of steam thereto and theexhaust of steam therefrom, and adapted to be actuated for forward orreverse propulsion; a braking-control valve; a duet connecting saidcylinder with said brakingcontrol valve; a second duct connecting saidbraking-control valve with said relief valve; and

means operatively connecting said valve gear with said braking-controlvalve; whereby upon der; said jacket being in series iluid communicationwith said sections and intermediate said sections, and the water in saidjacket being adapted for heat-exchange with the steam in the cylinder; athrottle valve for regulating the flow of steam to the cylinder duringpropulsion; valvegear associated with the engine for` controlling flowof steam to the `cylinder and adapted to be actuated for forward orreverse propulsion; a pedal-controlled relief valve for controlling thecompression in said lcylinder during braking; a braking-control valveoperable to connect said relief valve for regulatory action upon closureof said throttle valve, and a member interconnecting saidbraking-control valve and said valvegear.

17. In a power plant for use in propulsion and for braking including asteam engine having a piston and a cylinder; a steam-generator; aheatving section-and a superheating section in said generator; meansforming a jacket for said cylinder; said jacket being in series fluidcommunication with said sections and intermediate said sections, and thewater in said jacket being adapted i or heat-exchange with the steam inthe cylinder; a throttle valve for regulating the flow of steam to saidcylinder during propulsion; valve-gear associated with the engine forcontrolling the flow of steam to the cylinder and adapted to be actuatedfor forward or reverse propulsion; a pedal-controlled relief valve forcontrolling the -pressure in said cylinder during braking; la.braking-control valve to adapt said relief valve for regulatory actionupon closure of said throttle valve; a member interconnecting saidbrakingcontrol valve and said valve-gear to effect operation of saidvalve-gear to-reverse position upon operation of said braking-controlvalve to braking position; a temperature-responsive device inheat-exchanging relation with the steam in said actuation of saidbraking-control valve said f valve-gear is conditioned for reversepropulsion, and the over-driven engine conditioned for braking actionunder the control of said relief valve; the heat of compressiongenerated in the steam during braking being given up to the water in thejacket. y

16. In a power plant for use in propulsion and for braking including asteam engine having a piston and a cylinder; a steam generator; aheating section and a superheating section in said generator; meansforming a jacket for said cylinsuperheating section; a feed-pump forinjecting water into said heating section; a burner for the steamgenerator; and means under the control of said temperature-responsivedevice and operatively connected for regulation of the feed-water andburner, said last-mentioned means including a mechanism actuated by saidinterconnecting member; steam-pressure-actuated means for controllingthe feed-pump and burner; said mechanism being effective, upon movementof said interconnecting member to shift said valvegear to reverseposition, to preserve control of the feed-pump and burner independentlyof the condition of the steam-pressure-actuated means,

18. In a power plant for use in propulsion and for braking including asteam engine having a piston and a cylinder, a steam generator, aheating section and a superheating section in said generator, meansforming a jacket for said cylinder, said jacket being in series fluidcommunication with said sections and intermediate said sec-y tions andthe water in said jacket being adapted for heat-exchange with the steamin the cylinder, a throttle valve for regulating the flow of steam tosaid cylinder during propulsion, valve-gear associated with the enginefor controlling the flow of steam to the cylinder and adapted to beactuated for forward or reverse propulsion, a

pedal-controlled relief valve for controlling the pressure in saidcylinder during braking, a device y feed-pump for injecting water intosaid heating section, a burner for the steam generator, a source ofelectric current; a rst electrical switch under the control of saidtemperature-responsive device electrically connecting said source withsaid pump for controlling flow of fluid therefrom, a second electricalswitch under the controlo! said temperature-responsive deviceelectrically connecting said source with said burner for controllingsaid burner, a third electrical switch controlled by steam pressure ofthe generator and controlling the electrical connections to said pumpand switch preserves the control of said pump and burner by saidtemperature-responsive device '10 irrespective of the condition of saidthird switch.

ABNER DOBLE.

